The present invention generally relates to lining of a tunnel and more particularly, to a method of and an apparatus for building a thin lining on a peripheral wall of the tunnel.
Conventionally, in methods of building a thin lining on a tunnel, it has been generally so arranged as shown in FIG. 1 that concrete c is sprayed on a peripheral wall of a tunnel b by using a concrete spraying machine a, etc. However, in the prior art methods, since the lining operation is performed after the tunnel has been excavated, such a dangerous phenomenon takes place that it is impossible to prevent the natural ground of the tunnel from becoming loose during a time period from completion of excavation of the tunnel to start of the lining operation, thereby resulting in fall of rocks during the lining operation. Furthermore, the prior art methods are disadvantageous in that since it is difficult to finish the peripheral wall of the tunnel smoothly during excavation of the tunnel, the peripheral wall of the tunnel becomes uneven with the result that the tunnel is likely to be locally damaged due to stress concentration.
Moreover, in the known methods, since spraying concrete is employed for building the thin lining on the tunnel, a number of splashes of the concrete and a large amount of dust due to spraying of the concrete are produced, so that it is impossible to prevent a large amount of the loss of the lining material or deterioration of the working environments and it becomes difficult to perform the lining operation at a site having a spring water.
In addition, the known methods have such an inconvenience that since the thin lining is built along the uneven peripheral wall of the excavated tunnel, it is impossible to perform the lining operation in conformity with design dimensions of a cross-section of the tunnel.